SONOS memory cell having high-K dielectric
View Patent ↗A semiconductor memory device may include an intergate dielectric layer of a high-K dielectric material interposed between a floating gate and a control gate. With this intergate high-K dielectric in place, the memory device may be erased using Fowler-Nordheim tunneling.
1. A memory device comprising:
a gate dielectric formed on a substrate;
a floating gate formed on the gate dielectric, the floating gate comprising a nitride material;
an intergate dielectric formed on the floating gate and including a first layer including a high-K material and a second layer of silicon dioxide formed under the first layer;
a control gate formed directly on the high-K material of the intergate dielectric; and
a programming circuit configured to erase a charge stored in the floating gate using Fowler-Nordheim tunneling, wherein performing the Fowler-Nordheim tunneling includes applying a negative voltage to the control gate and a positive voltage to the source area and the drain area.
2. The memory device of claim 1 , wherein the high-K material comprises at least one of silicon oxynitride, aluminum oxide, hafnium silicate, hafnium silicon oxynitride, hafnium silicon nitride, HfO 2 , ZrO 2 , or Ta 2 O 5 .
3. The memory device of claim 1 , wherein the high-K material has a K value greater than that of silicon dioxide.
4. The memory device of claim 1 , wherein the programming circuit is further configured to store charge in the floating gate using hot electron injection through the gate dielectric formed on the substrate.
5. The memory device of claim 1 , further comprising:
dielectric spacers positioned adjacent the gate dielectric, the floating gate, the intergate dielectric, and the control gate.
6. The memory device of claim 1 , further comprising:
a source area formed in a first active region of the substrate; and
a drain area formed in a second active region of the substrate.
7. The memory device of claim 1 , wherein the memory device is a SONOS-type memory cell.
8. An integrated circuit comprising:
an array of memory cells formed on a semiconductor substrate, each of the memory cells including:
a gate dielectric formed on the substrate,
a floating gate formed on the gate dielectric and comprising a nitride layer,
an intergate dielectric formed on the floating gate, the intergate dielectric including a first layer including a high-K material and a second layer of silicon dioxide formed under the first layer, and
a control gate formed directly on the high-K material of the intergate dielectric; and
a programming circuit configured to erase one or more of the memory cells in the array using Fowler-Nordheim tunneling, and further configured to store charge in the floating gate using hot electron injection through the gate dielectric formed on the substrate.
9. The integrated circuit of claim 8 , wherein the high-K material comprises at least one of silicon oxynitride, aluminum oxide, hafnium silicate, hafnium silicon oxynitride, hafnium silicon nitride, HfO 2 , ZrO 2 , or Ta 2 O 5 .
10. The integrated circuit of claim 8 , wherein the high-K material has a K value greater than that of silicon dioxide.